As a conventional gas circuit breaker, there is a gas circuit breaker disclosed in Patent Literature 1, for example. As shown in FIG. 1 of Patent Literature 1, a fixed contact and a movable contact come into contact with each other in a power-on state of the gas circuit breaker, and the movable contact comes into contact with a slide guide and is in an energized state. A heating chamber is surrounded by a wall formed of an insulating material, the fixed contact, and a nozzle. A part of the heating chamber communicates with an arc chamber through a spray slit. At the time of current breaking, the movable contact moves downward in the drawing to generate arc between the fixed contact and the movable contact. Some of gas heated to a high temperature by the arc flows into the heating chamber through the spray slit and is also discharged to an outlet port through a pressure chamber, and some flows to the movable-contact side. Arc and hot gas generated by a series of the breaking operation damage energizing members such as the fixed contact and the movable contact, and damage insulating materials such as the nozzle and the wall.
Furthermore, in a case of a gas circuit breaker shown in FIG. 2 of Patent Literature 1, in addition to a first fixed contact, a second fixed contact is provided on the movable-contact side to make an energized state among the first fixed contact, the movable contact, and the second fixed contact. At the time of current breaking, the movable contact moves downward in the drawing to generate arc between the first fixed contact and the movable contact. Burnout rings that are electrically connected respectively to the first and second fixed contacts are provided between the first and second fixed contacts. As the movable contact moves downward in the drawing, arc moves between the burning rings. Hot gas flows substantially in the same manner as in the case of FIG. 1 of the Patent Literature. Also in this case, arc and hot gas generated by the breaking operation damage energizing members such as the first fixed contact, the second fixed contact, the burnout rings, and the movable contact, and damage an insulating material of a wall.
In the hot gas flow as described above, particularly, high-temperature and high-speed hot gas flowing into the heating chamber from the spray slit travels in a straight line in a radial direction and collides with the wall, and then disperses in the heating chamber.